PHOENIX -- John Carlson wasn't the only player who restructured his contract to free up cap space for the Minnesota Vikings this week.

Left guard Charlie Johnson signed a new deal that cut his maximum compensation and his cap number for 2013 by $500,000, an NFL source said.

Johnson, 28, originally had a $500,000 roster bonus due on Saturday. He also was scheduled to make $2.95 million in base salary and a $50,000 workout bonus and had $250,000 available in "likely to be earned" incentives based on playing time.

The new deal increased the roster bonus to $750,000, erased the incentives and dropped his base salary to $2.45 million -- giving Johnson more money now to create more flexibility for the Vikings going forward.

His cap number dropped from $4.35 million to $3.85 million, which is at least slightly more palatable for a pedestrian guard entering the last non-voidable year of the contract he signed in July 2011.

The only other Vikings player with a roster bonus due on the fifth day of the league year, veteran receiver Michael Jenkins, was released on March 4.

Carlson signed his restructured contract on Tuesday morning before a portion of the backup tight end's base salary was scheduled to become fully guaranteed. That move dropped his 2013 cap number from $4 million to $2.55 million.

The surprise release of cornerback Antoine Winfield the same day freed up another $7.25 million, and there remains a chance defensive tackle Kevin Williams ($7.5 million base salary in 2013) or others could be asked to restructure in the weeks and months to come.

Pending the filings of the contracts signed late in the week by receiver Greg Jennings and quarterback Matt Cassel, the Vikings were about $13.8 million under the salary cap.